1. Technical Field
The present invention relates to a piezoelectric device in which a plurality of piezoelectric elements is arranged in parallel, a liquid ejecting head including the piezoelectric device, a liquid ejecting apparatus including the liquid ejecting head, and a manufacturing method of the piezoelectric device.
2. Related Art
A liquid ejecting apparatus is an apparatus which includes a liquid ejecting head and ejects various types of liquid from the liquid ejecting head. As an example of such a liquid ejecting apparatus, there is an image recording apparatus such as an ink jet type printer or an ink jet type plotter, and recently, the liquid ejecting apparatus has been applied to various types of manufacturing apparatuses for the characteristic thereof that a very small amount of liquid can be landed accurately on a predetermined position. For example, the liquid ejecting apparatus has been applied to a display manufacturing apparatus which manufactures a color filter such as a liquid crystal display, an electrode forming apparatus which forms an electrode for an organic electro luminescence (EL) display, a field emission display (FED), or the like, and a chip manufacturing apparatus which manufactures a bio chip (biochemical element). A recording head of the image recording apparatus ejects ink of a liquid type, and a color material ejecting head for the display manufacturing apparatus ejects a solution of each color material of R (Red), G (Green), and B (Blue). In addition, an electrode material ejecting head for the electrode forming apparatus ejects an electrode material of a liquid type, and a biochemical organic substance ejecting head for the chip manufacturing apparatus ejects a bio organic substance solution.
The liquid ejecting head described above includes a plurality of pressure chambers and a piezoelectric device which generates the pressure fluctuation in liquid inside each pressure chamber. The piezoelectric device is configured to have a vibration plate which divides one side of the pressure chamber (for example, a side opposite to a nozzle plate on which nozzles are formed) and a piezoelectric element formed in every pressure chamber on the vibration plate. Here, the piezoelectric element is configured to have, for example, a lower electrode layer which functions as an individual electrode formed in every pressure chamber, a piezoelectric layer made of lead zirconate titanate (PZT), or the like and an upper electrode layer which functions as a common electrode common to a plurality of the pressure chambers, the layers sequentially stacked in this order from a side close to the vibration plate with a film deposition technology (for example, JP-A-2009-172878). In addition, a part of the piezoelectric layer sandwiched between the upper electrode layer and the lower electrode layer is a function portion which is deformed by applying a voltage to both electrode layers.
Here, when the piezoelectric layer is relatively thinner than the vibration plate, the rigidity of a part (arm portion) of the pressure chamber in which the piezoelectric layer is removed relatively increases so that the deformation of the piezoelectric element and the vibration plate is suppressed. Further, a problem in that reliability of the piezoelectric body itself deteriorates, or the like is generated. On the other hand, when the piezoelectric layer is relatively thicker than the vibration plate, rigidity of the piezoelectric element increases so that deformation efficiency of the piezoelectric element and the vibration plate deteriorate; however, reliability of the piezoelectric body is improved. Accordingly, deformation of the piezoelectric element and the thickness of the piezoelectric body (reliability) are inconsistent with each other.